System, apparatus and method for generating sound

ABSTRACT

A method for generating sound with a motor, including: generating a motor-driving signal having an audio signal component; applying the motor-driving signal to the motor, wherein the motor-driving signal drives the motor to generate a sound corresponding to the audio signal component; applying a bandpass filter to the motor-driving signal to generate a filtered motor-driving signal; and applying the filtered motor-driving signal to a speaker to present audio content consistent with the sound generated by the motor.

CROSS-REFERENCE TO RELATED APPLICATIONS

This application is a continuation of application Ser. No. 15/727,784,filed on Oct. 9, 2017, which is a continuation of InternationalApplication No. PCT/CN2015/089691, filed on Sep. 16, 2015, the entirecontents of both of which are incorporated herein by reference.

COPYRIGHT NOTICE

A portion of the disclosure of this patent document contains materialwhich is subject to copyright protection. The copyright owner has noobjection to the facsimile reproduction by anyone of the patent documentor the patent disclosure, as it appears in the Patent and TrademarkOffice patent file or records, but otherwise reserves all copyrightrights whatsoever.

FIELD

The disclosed embodiments relate generally to audio signal processingand more particularly, but not exclusively, to systems, apparatuses andmethods for generating sound.

BACKGROUND

Mobile platforms, such as manned and unmanned vehicles, can be used forperforming surveillance, reconnaissance, and exploration tasks formilitary and civilian applications.

For example, an unmanned aerial vehicle (UAV) may be outfitted with afunctional payload, such as a sensor for collecting data from thesurrounding environment or a substance to be delivered to a destination.Even though UAV technology has had great development, furtherimprovements are always desired.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is an exemplary top level diagram illustrating an embodiment of asystem for generating sound via a motor.

FIG. 2 is an exemplary top-level flow chart illustrating an embodimentof a method for generating sound using the motor of FIG. 1.

FIG. 3 is an exemplary top-level flow chart illustrating an alternativeembodiment of the method of FIG. 2, wherein the motor-driving signal isprovided.

FIG. 4 is an exemplary top-level flow chart illustrating anotheralternative embodiment of the method of FIG. 2, wherein the methodfurther comprises producing a motor-driving signal with an audio signalcomponent.

FIG. 5 is an exemplary top-level flow chart illustrating anotheralternative embodiment of the method of FIG. 2, wherein themotor-driving signal is retrieved from a memory.

FIG. 6 is an exemplary diagram illustrating an alternative embodiment ofthe system of FIG. 1, wherein the motor is installed on a mobileplatform.

FIG. 7 is an exemplary diagram illustrating an embodiment of the motorof FIG. 1.

FIG. 8 is an exemplary detail drawing illustrating an alternativeembodiment of the motor of FIG. 1, wherein the motor is configured togenerate a rotating motion.

FIGS. 9-10 are exemplary detail drawings illustrating other respectivealternative embodiments of the motor of FIG. 1, wherein a rotor of themotor is configured to assume an equilibrium position.

FIGS. 11-12 are exemplary detail drawings illustrating still otherrespective alternative embodiments of the motor of FIG. 1, wherein themotor is configured to generate a vibrating motion.

FIG. 13 is an exemplary diagram illustrating another alternativeembodiment of the system of FIG. 1, wherein the system includes a motorcasing that at least partially encloses a motor.

FIG. 14 is an exemplary diagram illustrating an embodiment of a motorcontroller for the motor of FIG. 1.

FIG. 15 is an exemplary diagram illustrating a waveform of a sinusoidalwave for modulating a pulsing signal using a motor controller of FIG.14.

FIGS. 16-21 are exemplary detail diagrams illustrating respectivealternative embodiments of the motor controller of FIG. 14, wherein themotor controller produces one or more motor-driving signals.

FIG. 22 is an exemplary diagram illustrating an alternative embodimentof the system of FIG. 6, wherein a main controller sends an audio signalto a motor controller.

FIGS. 23-24 are exemplary diagrams illustrating respective alternativeembodiments of the system of FIG. 1, wherein a motor controller of thesystem includes a decoder.

FIGS. 25-26 are exemplary diagrams illustrating respective alternativeembodiments of the system of FIG. 1, wherein the motor controller of thesystem includes a signal converter.

FIG. 27 is an exemplary diagram illustrating another alternativeembodiment of the system of FIG. 1, wherein a motor-driving signal isdemodulated.

FIG. 28 is an exemplary diagram illustrating another alternativeembodiment of the system of FIG. 1, wherein the motor-driving signal isfiltered.

FIG. 29 is an exemplary diagram illustrating an embodiment of anapparatus for controlling the motor of FIG. 1.

It should be noted that the figures are not drawn to scale and thatelements of similar structures or functions are generally represented bylike reference numerals for illustrative purposes throughout thefigures. It also should be noted that the figures are only intended tofacilitate the description of the preferred embodiments. The figures donot illustrate every aspect of the described embodiments and do notlimit the scope of the present disclosure.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

A UAV is usually controlled either autonomously by onboard computers orby the remote control of a pilot on the ground. The UAV needs to informa human of status of the UAV and error message related to components ofthe UAV such as the onboard computers and sensors.

When the disclosed systems, apparatuses, and methods are not used,communication between a mobile platform and a human is often not easy.For example, UAVs present information to a human via indicator lights.The number of indicator lights that are turned on and the combination ofcolors of the indicator lights can correspond to a message. A humanneeds to look up the corresponding message in a user manual, whichrequires time and labor. The UAVs may also present information to ahuman via a single pitch beep sound. However, a human still needs tolook up in a user manual for the message corresponding to the beep.Further, the beep sound is a monotonous sound, so amount of informationthat can be conveyed by such a sound is significantly limited.

Since currently-available visual and audio communication methods betweena mobile platform and a human do not provide rich information in amanner that is naturally comprehensible to the human, systems andmethods for producing high-quality sound using a mobile platform withouta need to install additional hardware can prove desirable and provide abasis for a wide range of system applications. Exemplary application caninclude conveying warning, error message, and/or entertainment contentto an operator or other user of the mobile platform.

The present disclosure sets forth systems, apparatuses, and methods forgenerating sound, overcoming disadvantages of prior systems and methods.Thus, the disclosure set forth herein provides solutions to thetechnical problems of efficient communication between a mobile platformand another entity, and further contributes advancement of mobileplatform technology as well as audio signal processing technology.

This above solutions can be achieved, according to one embodimentdisclosed herein, by a system 100 as illustrated in FIG. 1.

Turning to FIG. 1, the system 100 is shown as including a motorcontroller 200. The motor controller 200 can include a processor 210 forperforming data acquisition, data processing, and any other functionsand operations described herein for controlling an operation of themotor controller 200. Without limitation, the motor controller 200 caninclude one or more general purpose microprocessors (for example, singleor multi-core processors), application-specific integrated circuits,application-specific instruction-set processors, graphics processingunits, physics processing units, digital signal processing units,coprocessors, network processing units, audio processing units,encryption processing units, and the like. Although described asincluding a single processor 210 for purposes of illustration only, themotor controller 200 can include any suitable number of uniform and/ordifferent processors 210.

Optionally, the motor controller 200 can further include one or morediscrete circuits (not shown). The discrete circuits can useinterconnected individual resistors, capacitors, diodes, transistors,and other components to achieve the circuit function. The motorcontroller 200, for example, can include the processor 210 and/or thediscrete circuits for performing at least a portion of, or all of, thedisclosed functions of the motor controller 200.

The motor controller 200 can be configured to produce a motor-drivingsignal 240 according to an audio signal (not shown). Thus, themotor-driving signal 240 produced according to the audio signal caninclude an audio signal component that is based upon the audio signal.The audio signal can refer to a representation of a sound 320. Anexemplary audio signal can include an electrical voltage signal and/oran electrical current signal.

The sound 320 represented by the audio signal can include vibration thatpropagates as a mechanical wave of pressure and displacement through amedium. An exemplary medium can include solids, gases (such as air),liquids (such as water) and/or the like. The sound 320 can include anaudible sound having a frequency within a limit of human hearing, i.e.,a frequency ranging from 20 Hz to 20 kHz. Additionally and/oralternatively, the sound 320 can include a mechanical wave having afrequency outside the limit of human hearing. That is, the sound 320 canhave a frequency less than 20 Hz and/or greater than 20 kHz. Forexample, the sound 320 can include an ultrasound wave and/or aninfrasound wave.

On one hand, the audio signal may be synthesized directly or mayoriginate at a transducer. An exemplary transducer can include amicrophone, musical instrument pickup, phonograph cartridge, or tapehead. For example, the microphone can be an acoustic-to-electrictransducer and/or sensor that can convert a sound into an audio signal.On the other hand, a loudspeaker and/or a headphone can convert theaudio signal into a sound. The audio signal can be an analog signaland/or a digital signal.

As shown in FIG. 1, the system 100 can further include a motor 300coupled to the motor controller 200. The motor 300 can include anymachine configured to convert one form of energy into mechanical energy.An exemplary motor 300 can include a brushless motor, a direct current(DC) motor, a stepper motor, an alternating current (AC) inductionmotor, and/or a brushed motor, without limitation.

The motor controller 200 can be configured to drive the motor 300 withthe motor-driving signal 240 to generate the sound 320 corresponding tothe audio signal. The motor 300 can generate the sound 320 thatcorresponds to the audio signal. Stated somewhat differently, themotor-driving signal 240 with an audio signal component can be appliedto the motor 300. Thereby, when driven by the motor-driving signal 240,the motor 300 can generate the sound 320 that corresponds to the audiosignal component.

The motor-driving signal 240 can include any signal that enables themotor 300 to generate a mechanical motion. An exemplary motor-drivingsignal 240 can include an electric voltage signal, an electric currentsignal, a magnetic signal, and/or an optical signal, without limitation.In some embodiments, the motor-driving signal 240 can include a pulsingsignal. An exemplary pulsing signal can include a pulsing voltage signaland/or a pulsing current signal.

FIG. 2 is an exemplary top-level flow chart illustrating an embodimentof a method 1000 for generating sound using the motor 300 of FIG. 1.According to FIG. 2, the motor-driving signal 240 is applied, at 1100,to the motor 300. The motor controller 200 (shown in FIG. 1) can applythe motor-driving signal 240 to the motor 300.

For example, the motor controller 200 can be coupled with the motor 300via a motor-driving signal line 230 (shown in FIG. 6), and/or any othersuitable driving circuits (not shown). The motor 300 can include astator coil (shown in FIGS. 8-12). A current passing through the statorcoil to generate a magnetic field. The motor-driving signal line 230 canbe coupled with the stator coils. Therefore, apply the motor-drivingsignal 240 to the motor 300 can include transmitting the motor-drivingsignal 240 to the stator coils via the motor-driving signal line 230.The stator coils can generate the magnetic field according to themotor-driving signal 240.

As shown in FIG. 2, the motor 300 is enabled, at 1200, to generate thesound 320 corresponding to an audio signal component of themotor-driving signal 240. The motor-driving signal 240 can drive themotor 300 to generate a mechanical motion. The mechanical motion canpump sound waves into the medium surrounding the motor 300 and towards ahuman (not shown) and/or a wave-sensing instrument (not shown). When thesound 320 includes an audible sound within the limit of human hearing, ahuman ear can perceive the sound.

FIG. 3 is an exemplary top-level flow chart illustrating an alternativeembodiment of the method 1000 of FIG. 2, wherein the motor-drivingsignal is provided. According to FIG. 27, the motor-driving signal 240can be provided, at 1010, in accordance with the audio signal. The motorcontroller 200 (shown in FIG. 1) can provide the motor-driving signal240 using any suitable processes.

FIG. 4 is an exemplary top-level flow chart illustrating anotheralternative embodiment of the method of FIG. 2, wherein the methodfurther comprises producing the motor-driving signal 240 with an audiosignal component. According to FIG. 4, the motor-driving signal 240 canbe produced, at 1012, in accordance with the audio signal. In otherwords, providing the motor-driving signal 240 (shown in FIG. 3) caninclude producing the audio signal. For example, the motor controller200 (shown in FIG. 1) can provide the motor-driving signal 240 using anysuitable processes. Exemplary structures of the motor controller 200 areshown in FIGS. 14, 16-21, and/or 29.

FIG. 5 is an exemplary top-level flow chart illustrating anotheralternative embodiment of the method of FIG. 2, wherein themotor-driving signal 240 is retrieved from a memory. According to FIG.5, the motor-driving signal 240 can be retrieved, at 1014, from a memory(not shown). In other words, providing the motor-driving signal 240(shown in FIG. 3) can include retrieving the motor-driving signal 240from a memory. For example, the motor controller 200 (shown in FIG. 1)can retrieve the motor-driving signal 240 from a memory 220 and/or amemory 420 (shown in FIG. 6).

The motor-driving signal 240 can be produced in accordance with an audiosignal. For example, the motor-driving signal 240 can be produced byencoding the audio signal into a carrier signal. In some embodiments,the encoding can include modulating the carrier signal with the audiosignal.

For example, the carrier signal can include a pulsing signal. Thecarrier signal can be modulated with the audio signal using any pulsewave modulation techniques. Exemplary modulate techniques can includepulse-width modulation (PWM) (or pulse-duration modulation),pulse-amplitude modulation (PAM), pulse-code modulation (PCM),pulse-density modulation (PDM), and/or pulse-position modulation (PPM).

FIG. 6 is an exemplary diagram illustrating an alternative embodiment ofthe system 100 of FIG. 1. The exemplary system 100 can installed on,and/or integrated with a mobile platform 900. Stated somewhatdifferently, the motor 300 and/or the motor controller 200 can beinstalled aboard the mobile platform 900. The system 100 thereby can beat least partially positioned aboard the mobile platform 900.

Examples of the mobile platform 900 can include, but are not limited to,bicycles, automobiles, trucks, ships, boats, trains, helicopters,aircraft, various hybrids thereof, and the like. In some embodiments,the mobile platform 900 is an unmanned aerial vehicle (UAV).Colloquially referred to as “drones,” UAVs are aircraft without a humanpilot (or operator) onboard the vehicle whose flight is controlledautonomously or by a remote pilot (or sometimes both). UAVs are nowfinding increased usage in civilian applications involving variousaerial operations, such as data-gathering or delivery. The presentsystems and methods are suitable for many types of UAVs including,without limitation, quadcopters (also referred to a quadrotorhelicopters or quad rotors), single rotor, dual rotor, trirotor,hexarotor, and octorotor rotorcraft UAVs, fixed wing UAVs, and hybridrotorcraft-fixed wing UAVs.

As shown in FIG. 6, the motor controller 200 can optionally include amemory 220 coupled with the processor 210. Exemplary memory 220 caninclude, but is not limited to, random access memory (RAM), static RAM,dynamic RAM, read-only memory (ROM), programmable ROM, erasableprogrammable ROM, electrically erasable programmable ROM, flash memory,secure digital (SD) card, etc.). The memory 220 can be configured tostore data files, and coded instructions. For example, the data filescan include an audio file for storing the audio signal in acomputer-readable format. The coded instructions can includeinstructions for operating the motor when executed by the processor 210.

The processor 210 can be configured to execute the coded instructionsfor implementing methods as disclosed herein. Although described asincluding a single memory 220 for purposes of illustration only, themotor controller 200 can include any suitable number of uniform and/ordifferent memories 220.

The motor controller 200 can include a communication module 260 coupledwith the processor 210 and/or the memory 220. The communication module260 can include a digital communication interface and/or an analogcommunication interface. The communication module 260 can be configuredto receive data and/or control signal from the motor controller 200and/or to send a motor-control signal 240 to the motor 300. Further, thecommunication module 260 can include a transceiver, a transmitter and/ora receiver that can include radio frequency (or RF) circuitry or anyother appropriate hardware and any appropriate software instructing thehardware for receiving and/or transmitting data via a wired or wirelessconnection with an electronic device. Although described as including asingle communication module 260 for purposes of illustration only, themotor controller 200 can include any suitable number of uniform and/ordifferent communication modules 260.

FIG. 6 shows the system 100 as further including a main controller 400.The main controller 400 can be configured to perform data acquisition,data processing, and any other functions and operations for controllingan operation of the mobile platform 900. The main controller 400 can beinstalled onboard the mobile platform 900. Additionally and/oralternatively, the main controller 400 include a remote controller (notshown) configured to control the mobile platform 900 remotely.

The main controller 400 can include a processor 410, a memory 420coupled with the processor 410, and/or a communication module 460coupled with the processor 410 and/or the memory 420. The communicationmodule 460 can include a digital communication interface and/or ananalog communication interface. The communication module 460 can beconfigured to transmit data and/or control signal to the motorcontroller 200. Further, communication interface 460 can include atransceiver, a transmitter and/or a receiver that can include RFcircuitry or any other appropriate hardware and any appropriate softwareinstructing the hardware for receiving and/or transmitting data via awired and/or wireless connection with an electronic device.Advantageously, the communication interface 460 of the main controller400 preferably is compatible with, and can communicate with, thecommunication module 260 of the motor controller 200.

Although shown and described as including a single processor 410, asingle memory 420 and a single communication module 460 for purposes ofillustration only, the main controller 400 can include any suitablenumber of uniform and/or different processors 410, any suitable numberof uniform and/or different memories 420, and any suitable number ofcommunication modules 460.

The main controller 400 can be coupled with the motor controller 200 viaa control signal line 430 and/or a data communication line 440. FIG. 6further illustrates the motor controller 200 as being coupled with themotor 300 via a motor-driving signal line 230. The motor-driving signal240 can be transmitted to the motor 300 from the motor controller 200via the motor-driving signal line 230. The motor-driving signal line230, the control signal line 430 and/or the data communication line 440can include any conventional wired and/or wireless communicationinput/output interface, circuit, and/or wiring.

Communication between the motor controller 200, the motor 300, and themain controller 400 can be wired and/or wireless. Further, although themotor controller 200 is illustrated in FIG. 6 as separate from the maincontroller 400, the motor controller 200 can be at least partiallyintegrated with the main controller 400.

When the system 100 is installed on the mobile platform 900, the motor300 can be configured to enable the mobile platform 900 to move. Forexample, the motor 300 can be coupled with a propulsion mechanism 310.The propulsion mechanism 310 can include any structure for creating aforce leading to a movement of the mobile platform 900. For example, thepropulsion mechanism 310 can include one or more propellers driven bythe motor 300 to rotate for generating thrust for propelling the mobileplatform 900. Therefore, by being coupled with the propulsion mechanism310, the motor 300 can be configured to enable the mobile platform 900to move.

In addition to enabling the mobile platform 900 to move, the motor 300can be driven by the motor controller 200 to generate the sound 320. Thesound 320 can include a sound wave in and/or out of the frequency rangeof human hearing, and can include one or more frequency components. Thesound 320, for example, can include music, speech, or a combinationthereof. Additionally and/or alternatively, exemplary sound 320 caninclude a sound produced by an animal, a machine, and/or a naturalphenomenon (i.e., an animal sound, a machine sound, a natural sound),without limitation.

Additionally and/or alternatively, the system 100 can include any othermachine or other mechanism for generating motion, not limited to themobile platform 900. For example, the system 100 can include a clock, atimer, a dial indicator, a wind-up toy, a music box, and/or the like.The propulsion mechanism 310 can thus include one or more propellersand/or one or more gears driven by the motor 300 to generate the motionof the system 100.

FIG. 7 is an exemplary diagram illustrating an embodiment of the motor300 of FIG. 1. FIG. 7 illustrates the motor 300 as including a movabledevice 330 and/or a stationary device 340 coupled with the movabledevice 330 via an interaction 350. The interaction 350 can be generatedand/or adjusted by the motor-driving signal 240. The interaction 350 caninclude a mechanical, electric, magnetic, optical, chemical, and/orbiological force that is configured to generate a motion of the movabledevice 330.

The interaction 350 can enable the movable device 330 to be located atan equilibrium position 380 relative to the stationary device 340.Further, the interaction 350 can be generated and/or changed via themotor-driving signal 240 (shown in FIG. 1) from the motor controller 200(shown in FIG. 1). The interaction 350 can be generated and/or changed,for example, in such a way as to generate a vibration 370 of the movabledevice 330 relative to the equilibrium position 380. In other words, themotor controller 200 can be configured to vibrate the movable device 330relative to the equilibrium position 380 based upon the motor-drivingsignal 240. The vibration can be directed along one or more axes of themovable device 330 (or motor 300).

To further illustrate the interaction 350, FIG. 8 shows an exemplarydetail drawing illustrating an alternative embodiment of the motor 300of FIG. 1. The motor 300 can be configured to generate a rotatingmotion. For illustrative purposes, FIG. 8 shows the motor 300 as athree-phase brushless direct current (BLDC) motor. However, the motor300 is not limited to the three-phase BLDC motor.

In FIG. 8, the stationary device 340 is shown as including a stator 341.The stator 341 can include three stator coil pairs A1/A2, B1/B2, C1/C2.The stator coil pair A1/A2 includes coils A1, A2. The stator coil pairB1/B2 includes coils B1, B2. The stator coil pair C1/C2 includes coilsC1, C2. Each of the stator coil pairs A1/A2, B1/B2, C1/C2 can functionas a magnetized pole pair when an electric current passes the coil(s)A1, A2, B1, B2, C1, C2. Optionally, each of the coils A1, A2, B1, B2,C1, C2 can wrap around a core of soft ferromagnetic material such assteel, to enhance a magnetic field produced by the coil.

The movable device 330 can include a rotor 331 rotatable relative to thestator 341. The rotor 331 can include at least one magnet, such as apermanent magnet. Further, although FIG. 8 shows the motor 300 having aninner rotor, i.e., the rotor 331 being surrounded by the stator 341, themotor 300 can additionally and/or alternatively have an outer rotor. Theouter rotor can refer to a rotor that surrounds a stator. When the motor300 has the outer rotor, the disclosed method, apparatus and/or systemcan be equivalently and/or similarly implemented.

Although FIG. 8 illustrates the moveable device 330 as being a rotor,the moveable device 330 can include a movable component that cangenerate a motion other than rotation. For example, alternatively and/oradditionally, the motor 300 can include a linear motor. The movabledevice 330 can generate a linear motion.

A pulsed DC current can be provided to the stator coil pairs A1/A2,B1/B2, C1/C2 at a synchronous speed (or rate) to create a rotatingmagnetic field. The magnetic field of each stator coil pair can begenerated at synchronous speed.

For example, as shown in an electric current diagram 360 in FIG. 8, thestator coil pair A1/A2 can be first provided with a DC pulse 361A, whichmagnetizes the coil A1 as a north pole and the coil A2 as a south pole,drawing the rotor 331 into an initial position. As the rotor 331 passesthe first magnetized pole pair, in this case the stator coil pair A1/A2,the current/voltage to the coil pair A1/A2 can be switched off. The nextstator coil pair C1/C2 can be provided with a DC pulse 361C causing thecoil C1 to be magnetized as a south pole and the coil C2 to be a northpole. The rotor 331 can then rotate clockwise to align with the statorcoil pair B1/B2. By pulsing the stator coil pairs A1/A2, B1/B2, C1/C2 insequence, the rotor 331 can continue to rotate clockwise to keep beingaligned with the stator coil pairs A1/A2, B1/B2, C1/C2. The speed (orrate) of rotation can be controlled by the frequency of the pulse andthe torque by the current and/or voltage of the pulse.

When no electric signal is applied to the stator coil pairs A1/A2,B1/B2, C1/C2, the rotor 331 can assume a predetermined orientationrelative to the stator 341 and may be in alignment with the stator 341and/or out of alignment with the stator 341. However, when a constantmagnetic field is formed, the rotor 331 can be aligned with the constantmagnetic field. A position of the rotor 331 that aligns with theconstant magnetic field can be referred to as the equilibrium position380 (shown in FIG. 7) of the rotor 331. Further, when the direction ofan effective magnetic field oscillates relative to the direction of theconstant magnetic field, the rotor 331 can vibrate relative to theequilibrium position 380.

FIG. 9 is an exemplary detail drawing illustrating another alternativeembodiment of the motor 300 of FIG. 1. FIG. 9 illustrates the rotor 331of the motor 300 as assuming the equilibrium position 380.

In FIG. 9, the stator coil pair A1/A2 can be first provided with a DCsignal 362A, which magnetizes the coil A1 as a north pole and the coilA2 as a south pole. The DC signal 362A provided to the stator coil pairA1/A2 can remain constantly on. No signal is provided to the stator coilpairs B1/B2, C1/C2. Thus, the constant magnetic field 351 can beestablished, and the rotor 331 can assume the equilibrium position 380in order to align with the constant magnetic field 351. In the exampleshown in FIG. 9, the rotor 331 is aligned with the stator coil pairA1/A2.

FIG. 10 is an exemplary detail drawing illustrating another alternativeembodiment of the motor 300 of FIG. 1. FIG. 10 illustrates the rotor 331of the motor 300 as assuming the equilibrium position 380.

In FIG. 10, in addition to a first DC signal 362A provided to the statorcoil pair A1/A2, a second DC signal 362B can be provided to the statorcoil pair B1/B2. Magnetic fields 351, 352 respectively formed by thestator coil pair A1/A2 and the stator coil pair B1/B2 can sum into aconstant magnetic field 354. The rotor 331 can assume the equilibriumposition 380 in order to align with the constant magnetic field 354. Inthe example shown in FIG. 7, the rotor 331 is aligned halfway betweenthe stator coil pair A1/A2 and the stator coil pair B1/B2.

Although not shown in FIGS. 9-10, a third DC signal can further beapplied to the respective stator coil pair C1/C2. Therefore, differentand/or uniform DC signals can be applied to the respective stator coilpairs A1/A2, B1/B2, C1/C2, to control the rotor 331 to assume anequilibrium position 380 corresponding to the DC signals, withoutlimitation.

FIG. 11 is an exemplary detail drawing illustrating another alternativeembodiment of the motor 300 of FIG. 1, wherein the motor 300 isconfigured to generate a vibrating motion. In FIG. 11, an oscillatingsignal 363A is superimposed on, and/or combined with, the first DCsignal 362A. Further, the oscillating signal 363A can be inverted toform an oscillating signal 363B. The oscillating signal 363B can besuperimposed on, and/or combined with, the second DC signal 362B and insynchronization with the oscillating signal 363A. Thus, the magneticfields formed by the stator coil pair A1/A2 and the stator coil pairB1/B2 can sum into an effective magnetic field 355.

The directions of magnetic fields respectively formed by the stator coilpair A1/A2 and the stator coil pair B1/B2 can be different. Further, adifference between magnitudes of the magnetic fields respectively formedby the stator coil pair A1/A2 and the stator coil pair B1/B2 canoscillate between a negative value and a positive value. The directionof the effective magnetic field 355 can thus oscillate relative to thedirection of the constant magnetic field 354. Accordingly, the rotor 331can vibrate relative to the equilibrium position 380.

Directions and magnitude of magnetic fields and signals in FIGS. 8-11are exemplary only. Magnitude and/or polarity of the oscillating signals363A, 363B can be uniform and/or different. Magnitude and/or polarity ofthe DC signals 362A, 362B can be uniform and/or different. As indicatedin FIG. 11, the direction of the effective magnetic field 355 canoscillate relative to the direction of the constant magnetic field 354.

Under the effective field 355, the rotor 331 can waver circumferentially(i.e., counter-clockwise and/or clockwise). For illustrative purposes,FIG. 11 shows the effective field 355 distributing on both sides of theconstant magnetic field 354. However, the effective field 355 can belocated on one side of the constant magnetic field 354. Position of theeffective field 355 relative to the constant magnetic field 354 can beadjusted based on magnitude and/or polarity of the signals 363A, 363B,362A, 362B. The constant magnetic field 354 can determine theequilibrium position 380. Accordingly, the rotor 331 “oscillatingrelative to the equilibrium position 380” can refer to the rotor 331oscillating between two positions on different sides and/or uniformsides of the constant magnetic field 354.

Additionally and/or alternatively, under the effective field 355, therotor 331 can vibrate in a radial direction, i.e., in a direction of theeffective field 355. The magnitude of the effective field 355 at a pointin time can vary based on magnitude and/or polarity of the signals 363A,363B, 362A, 362B at the respective point in time. The rotor 331 canchange shape and/or dimension due to magnetostriction. Magnetostrictioncan refer to a property of ferromagnetic materials of changing shapeand/or dimensions during a process of magnetization. When the rotor 331is made of a ferromagnetic material, the rotor 331 can change shapeand/or dimension. Such change can result in a vibration of the rotor 331in the radial direction, where the rotor 331 can be effectively pulledand pushed radially. In one example, when the rotor 331 is an outerrotor (not shown) fixed on a magnetic yoke (not shown), the rotor 331can exert stress on the magnetic yoke. The rotor 331 and/or the magneticyoke can be effectively pulled and pushed radially, resulting in achange in shape of the rotor 331 and/or the magnetic yoke.

Although FIG. 11 illustrates the rotor 331 as being vibrated by applyingan electrical signal to more than one stator coil pair, vibrating therotor 331 does not necessarily need to involve more than one stator coilpair. For example, FIG. 12 is an exemplary detail drawing illustratinganother alternative embodiment of the motor 300 of FIG. 1, wherein themotor 300 is configured to generate a vibrating motion. In FIG. 12, theoscillating signal 363A is superimposed on, and/or combined with, the DCsignal 362A that is provided to the stator coil pair A1/A2. Theoscillating signal 363A can be summed with the DC signal 362A to form asignal oscillating between a negative value and a positive value. Thus,even without a signal provided to the stator coil pairs B1/B2, C1/C2,the magnetic field formed by the stator coil pair A1/A2 can oscillatebetween the constant magnetic field 351 and an opposite magnetic field356. Accordingly, the rotor 331 can vibrate relative to a directionbetween the constant magnetic field 351 and the opposite magnetic field356. For example, the rotor 331 can vibrate relative to an equilibriumposition 381 shown in FIG. 12. The position 381 is exemplary only andcan have a different orientation from the orientation illustrated inFIG. 12.

Therefore, the motor controller 200 can be configured to vibrate therotor 331 relative to the equilibrium position 380 based upon themotor-driving signal 240. Further, the system 100 can include a soundamplifier (not shown) for amplifying the sound 320. An exemplary soundamplifier can include a motor casing or other enclosure surrounding therotor 331 and/or the motor 300. FIG. 13 is an exemplary diagramillustrating another alternative embodiment of the system 100 of FIG. 1,wherein the system 100 includes a motor casing 390 that at leastpartially encloses the motor 300.

FIG. 13 illustrates the motor casing 390 as completely enclosing themain controller 400 and the motor controller 200. However, in certainexamples, at least one of the main controller 400 and/or the motorcontroller 200 can be at least partially located outside the motorcasing 390, without limitation. When the rotor 331 vibrates, the motorcasing 390 can vibrate accordingly. The motor casing 390 may vibratebecause the motor 330 is in mechanical connection with the motor casing390. The vibration 370 (as in FIG. 7) of the rotor 331 thereby canmechanically drive the motor casing 390 to vibrate.

In certain cases, the motor 330 may be suspended within the motor casing390 and surrounded by empty space in the motor casing 390 without beingin directly and/or mechanically connected with the motor casing 390. Thevibration 370 of the motor 300 may pump the surrounding medium, such asair, and thus exert a force for driving the motor casing 390 to vibrate.

The motor casing 390 can include a mounting base (not shown) by whichthe motor 300 can be coupled with the mobile platform 900. The motorcasing 390 can achieve an effect similar to an effect of diaphragmand/or cone in a loudspeaker. That is, the vibration of the motor casing390 can amplify the vibration 370 of the motor 300 and accordinglyamplify the sound 320. Additionally and/or alternatively, the vibration370 of the motor 300 may pump the surrounding medium, such as air, andthus exert a force for driving the stator 340 to vibrate.

The rotor 330 can vibrate based on the motor-driving signal 240 togenerate the sound 320. To produce the motor-driving signal 240 forgenerating the sound 320, the motor controller 200 can encode themotor-driving signal 240 with the audio signal.

FIG. 14 is an exemplary diagram illustrating an embodiment of a motorcontroller for the motor 300 of FIG. 1. As shown in FIG. 14, the motorcontroller 200 can obtain the audio signal 241. Exemplary processes forobtaining the audio signal 241 are illustrated in FIGS. 22-23.

The motor controller 200 can include an optional amplifier 212. Theamplifier 212 has a gain G for amplifying the audio signal 241. Theamplifier 212 thereby enables an amplitude of the vibration 370 (shownin FIG. 7) of the motor 300 to be increased. Thus, a volume of the sound320 likewise can be increased.

Additionally and/or alternatively, the motor controller 200 can includea DC signal unit 213 for superimposing a DC signal 2130 onto the audiosignal 241. The DC signal 2130 can function as an offset configured toadjust the equilibrium position 380 (shown in FIGS. 9-10) of the rotor330 relative to the stator 340.

The motor controller 200 can change and/or adjust a volume of the sound320 by adjusting the equilibrium position 380 of the rotor 330 of themotor 300 relative to the stator 340 of the motor 330. Even when theaudio signal 241 remains the same, a different equilibrium position 380can result in a different torque exerted on the rotor 330 by the stator340. Therefore, changing the equilibrium position 380 relative to thestator 340 can cause an amplitude of the vibration 370 (shown in FIG. 7)of the rotor 330 to change.

In certain embodiments, vibration of the rotor 330 may have a greateramplitude at an equilibrium position 380 aligned with the stator coilpair A1/A2 (as shown FIG. 9) than the equilibrium position 380 out ofalignment with the stator coil pair A1/A2 (as shown FIG. 7). In otherembodiments vibration of the rotor 330 may have a smaller amplitude atan equilibrium position 380 aligned with the stator coil pair A1/A2 (asshown FIG. 9) than the equilibrium position 380 out of alignment withthe stator coil pair A1/A2 (as shown FIG. 7). How the equilibriumposition 380 correlates with the amplitude may depend on specific designof the motor 300, and is not limited in the present disclosure. Forexample, the DC signals 362A, 362B can be respectively adjusted. When avolume of the sound 320 (shown in FIG. 7) reaches a maximum, the DCsignals 362A, 362B are at a respective optimal value.

Additionally and/or alternatively, the motor controller 200 can includea filter 214. An exemplary filter 214 can include a low-pass filterconfigured to filter and/or remove a high frequency component of theaudio signal 241. A cut-off frequency of the low-pass filter can beselected based on requirement of quality of the sound 320, withoutlimitation. An exemplary cut-off frequency of the low-pass filter can begreater than 20 kHz, so high-pitch audible noise can be removed from thesound 320. The sound 320 can be softer to a human ear and have animproved tone quality.

Additionally and/or alternatively, the motor controller 200 can includean adjustment member 215 for processing the audio signal 241 in such away as to improve the quality of the sound 320. The exemplary adjustmentmember 215 can include an equalizer for changing an amplitude of aselected frequency component of the audio signal 241, a reverb forcreating an echo effect of the sound 320, and/or a bass booster forboosting a low frequency component of the audio signal 241.

Additionally and/or alternatively, the motor controller 200 can includean encoder 216. The encoder 216 can be configured to produce themotor-driving signal 240 modulated with the audio signal 241 for drivingthe motor 300 to generate the sound 320. An exemplary motor-drivingsignal 240 can include a pulsing signal. In certain embodiments, thepulsing signal can include a pulsing current signal having an amplituderanging from 0.1 Amp to 0.5 Amp. In other embodiments, the pulsingsignal can include a pulsing voltage signal having an amplitude rangingfrom 5 V to 100 V.

For generating the vibration 370 and/or enabling the rotor 330 torotate, the motor controller 200 can produce the motor-driving signal240 with certain suitable control parameters. In certain illustrativeexamples, the audio signal 241 can have a frequency range from 20 Hz to20 kHz. The pulsing signal can have a frequency greater than 40 kHz, apulse width (and/or duty cycle) ranging from 0% to 100%, and/or aresolution ranging from 8-bit to 14-bit.

For enabling the rotor 330 to rotate and/or driving the propulsionmechanism 310, the motor controller 200 can produce the motor-drivingsignal 240 with certain suitable control parameters. In certainillustrative examples, the pulsing signal can have a frequency rangingfrom 10 kHz to 40 kHz, a pulse width (and/or duty cycle) ranging from 0%to 100%, and/or a resolution ranging from 8-bit to 16-bit.

An exemplary technique for producing the motor-driving signal 240modulated with the audio signal 241 can include pulse-width modulation(PWM). Pulse width modulation is a technique which can generate anoutput waveform (i.e., the motor-driving signal 240) that is switched onand off, resulting in the motor-driving signal 240 being high or low ata given time. The output waveform can then filtered by an inductance inthe motor 300 to average the output waveform. The average of themotor-driving signal 240 can be changed by adjusting a duty cycle. Theduty cycle can refer to a ratio of an ON portion time of the waveformcompared to an OFF portion time of the waveform. An example of asinusoidal wave to be encoded using PWM is shown in FIG. 15.

Any PWM method can be used for generating the motor-driving signal 240.In an exemplary PWM method, the duty cycle D can be calculated by:

$\begin{matrix}{{{Duty}\mspace{14mu} {cycle}} = {\frac{\left( {{V_{in} \times G} + {Offset}} \right) \times {Filter}}{V_{\max}} + {50\%}}} & {{Equation}\mspace{14mu} (1)}\end{matrix}$

where Vin is an input voltage of the audio signal 241, G is a gain ofthe amplifier 212, Offset is a value of the DC signal 2130, Filter is again of the filter 214, and Vmax is a peak-to-peak amplitude of theaudio signal 241.

FIG. 15 is an exemplary diagram illustrating a waveform of a sinusoidalwave 242 for modulating a pulsing signal using the motor controller 200of FIG. 14. For illustrative purposes, the example in FIG. 15 can haveG=1, Offset=0, Filter=1. Thus, according to Equation (1), at point D,Vin=0, duty cycle=50%. At point E, −(½)Vmax<Vin<0, 0<duty cycle<50%. Atpoint F, 0<Vin<(½)Vmax, 50%<duty cycle<100%. When the Offset is applied,for example, assuming the Offset=10% Vmax and Vin=0, duty cycle=60%.

Thus, at a certain time, a duty cycle of the pulsing signal cancorrespond to an input value of the sinusoidal wave. Using the PWMtechnique, the encoder 216 can produce the motor driving signal 240 insuch a way that, at any time, a duty cycle of the motor-driving signal240 can correspond to an input value of the audio signal inputted intothe encoder 216.

When the motor 300 includes a three-phase brushless DC motor (shown inFIGS. 8-12), the motor-driving signal 240 can be respectively providedto one or more of the three stator coil pairs A1/A2, B1/B2, C1/C2. FIG.16 is an exemplary detail diagram illustrating an alternative embodimentof the motor controller 200 of FIG. 14. FIG. 16 shows the motorcontroller 200 as producing motor-driving signals 240A, 240B, 240C tofeed to the stator coil pairs A1/A2, B1/B2, C1/C2, respectively. Themotor controller 200 can include amplifiers 212A, 212B, 212C, DC signalunits 213A, 213B, 213C, filters 214A, 214B, 214C, adjustment members215A, 215B, 215C, and encoders 216A, 216B, 216C. The DC signal units213A, 213B, 213C can be used for respectively superimposing DC signals2130A, 2130B, 2130C to the audio signal 241.

As shown in FIG. 16, the amplifiers 212B and/or 212C can have a gain of−G, which has an opposite sign from the gain +G of the amplifier 212A.Thus, the stator coil pairs A1/A2, B1/B2, C1/C2 can create a summedmagnetic field for vibrating the rotor 331 (shown in FIG. 8).

FIG. 17 is an exemplary detail diagram illustrating an alternativeembodiment of the motor controller 200 of FIG. 14. FIG. 17 shows thefilters 214A, 214B, 214C and the adjustment members 215A, 215B, 215C asbeing omitted from the motor controller 200. The motor-driving signals240A, 240B, 240C can be produced and provided to the stator coil pairsA1/A2, B1/B2, C1/C2, respectively, to generate the sound 320 (shown inFIG. 7).

FIG. 18 is an exemplary detail diagram illustrating an alternativeembodiment of the motor controller 200 of FIG. 14. FIG. 18 shows themotor controller 200 as applying the DC signal 2130A to the stator coilpairs A1/A2. The DC signals 2130B, 2130C applied to the stator coilpairs B1/B2, C1/C2 can be omitted. In this case, the rotor 330 may havethe equilibrium position 380 aligned with the stator coil pair A1/A2(shown in FIG. 9).

FIG. 19 is an exemplary detail diagram illustrating another alternativeembodiment of the motor controller 200 of FIG. 1. FIG. 19 shows theamplifier 212A and/or the amplifier 212B as having a positive gain +G.The amplifier 212C can have a negative gain −G. In such a case, theaudio signal can be inverted by the amplifier 212C. Thus, the audiosignal 241 can be inverted before being provided to the stator coilpairs C1/C2. The rotor 330 can thus vibrate according to the differencebetween the magnetic field formed by the stator coil pair C1/C2 and thesum of the magnetic fields generated by the stator coil pairs A1/A2,B1/B2.

FIG. 20 is an exemplary detail diagram illustrating an alternativeembodiment of the motor controller 200 of FIG. 14. FIG. 20 shows that nomotor-driving signal 240 is provided to the stator coil pair C1/C2. Theamplifier 212A can have a positive gain +G. The amplifier 212B can havea negative gain −G to invert the audio signal 241. The motor-drivingsignals 240A, 240B can drive the rotor 330 to vibrate according themechanism as shown in FIG. 8.

FIG. 21 is an exemplary detail diagram illustrating another alternativeembodiment of the motor controller 200 of FIG. 1. FIG. 21 shows that nomotor-driving signal is provided to the stator coil pairs B1/B2, C1/C2.Although the amplifier 212A is shown as having a positive gain +G, theamplifier 212A can have a negative gain −G, without limitation. Themotor-driving signals 240A can drive the rotor 330 to vibrate, accordingthe mechanism as shown in FIG. 12.

Configurations of the motor controller 200 are not limited to FIGS. 14,16-21. In order to generate the vibration 370 as shown in FIG. 2,parameters of the motor controller 200 can be adjusted to generate twocompeting magnetic fields. Respective directions of the two competingmagnetic fields can be different. Further, a difference betweenrespective magnitudes of the two competing magnetic fields can oscillatebetween a negative value and a positive value (shown in FIGS. 11-12).The two competing magnetic fields can enable the rotor 330 to vibrate.Any configuration of the motor controller 200 for generating such twocompeting magnetic fields can enable the rotor 330 to generate the sound320 and is within the scope of the present disclosure.

Further, the audio signal 241 can be a digital signal and/or an analogsignal. Configurations of the motor controller 200 as shown FIGS. 14,16-21 can be implemented by the processor(s) 210 and/or one or morediscrete circuits (not shown). In certain embodiments, the audio signal241 can be digital, and the configurations of the motor controller 200shown FIGS. 14, 16-21, and/or equivalents thereof, can be implemented bythe processor(s) 210. Advantageously, no additional hardware isnecessary for implementing the methods as disclosed herein, such as themethod 1000 in FIG. 2.

The audio signal 241 can be obtained using any suitable process. FIG. 22is an exemplary diagram illustrating another alternative embodiment ofthe system 100 of FIG. 1. The audio signal 241 can be stored on thememory 420 of the main controller 400. Additionally and/oralternatively, an audio file (not shown) can be stored on the memory 420on the main controller 400, and the main controller 400 can include adecoder (not shown) to decode the audio file into the audio signal 241.

The main controller 400 can send the audio signal 241 to the motorcontroller 200. The motor controller 200 can thus receive the audiosignal 241 from the controller 200 via the control signal line 430and/or the data communication line 440 coupling the main controller 400with the motor controller 200.

FIG. 23 is an exemplary diagram illustrating another alternativeembodiment of the system 100 of FIG. 1, wherein the motor controller 200includes an audio signal decoder 250. An exemplary audio signal decoder250 can be at least partially integrated in the processor(s) 210. Anaudio file 243 can be stored on the memory 420 on the main controller400. The main controller 400 can send the audio file 243 to the motorcontroller 200. The motor controller 200 can thus receive the audio file243 from the controller 200 via the control signal line 430 and/or thedata communication line 440 that couple the main controller 400 with themotor controller 200. The audio signal decoder 250 can be configured tocreate the audio signal 241 by decoding the audio file 243. The audiosignal decoder 250 can include a conventional decoding programexecutable using the processor(s) 210, and/or discrete circuits suitablefor decoding the audio file 243.

The audio file 243 can include a computer-readable file for storing theaudio signal 241 in any conventional format. Exemplary formats caninclude uncompressed audio formats, such as Waveform Audio File Format(WAV), Audio Interchange File Format (AIFF), Au file format (AU) and/orraw header-less Pulse-code modulation (PCM). Additionally and/oralternatively, the formats can include formats with losslesscompression, such as Free Lossless Audio Codec(FLAC), Monkey's Audio(filename extension .ape), WavPack (filename extension .wv), True Audiocodec (TTA), Adaptive Transform Acoustic Coding (ATRAC) AdvancedLossless, Apple Lossless Audio Codec (ALAC) (filename extension .m4a),Moving Picture Experts Group (MPEG)-4 Scalable to Lossless (SLS), MPEG-4Audio Lossless Coding (ALS), MPEG-4 Direct Stream Transfer (DST),Windows Media Audio Lossless (WMA Lossless), and/or Shorten (SHN).Additionally and/or alternatively, the formats can include formats withlossy compression, such as Opus (developed by the Internet EngineeringTask Force), MPEG-1 or MPEG-2 Audio Layer III(MP3), Vorbis developed bythe Xiph.Org Foundation, Somerville, Mass., United States), AdvancedAudio Coding (AAC), ATRAC and/or Windows Media Audio Lossy (WMA lossy).

FIG. 24 is an exemplary diagram illustrating another alternativeembodiment of the system of FIG. 1, wherein the motor controller 200includes the audio signal decoder 250. Further, the audio file 243 canbe stored on the memory 220 on the motor controller 200. The motorcontroller 200 can be configured to retrieve the audio file 243 from thememory 220. The audio signal decoder 250 can be configured to create theaudio signal 241 by decoding the audio file 243.

In certain cases, the audio signal 241 to be processed in the motorcontroller 200 (shown in FIGS. 14, 16-21) can be digital. In thosecases, the system 100 can be configured to execute an analog-to digitalconversion for an analog audio signal to generate the audio signal 241.FIG. 25 is an exemplary diagram illustrating another alternativeembodiment of the system 100 of FIG. 1, wherein the main controller 400of the system 100 can include a signal converter 470. The signalconverter 470 can include an analog-to-digital converter (ADC)configured to convert an analog audio signal 244 to the audio signal 241that is digital.

The main controller 400 can be configured to receive the analog audiosignal 244 using any suitable method. For example, the communicationmodule 460 (shown in FIG. 6) on the main controller 400 can receive aradio wave modulated with the audio signal 244. The processor(s) 410and/or other circuits on the main controller 400 can be configured todemodulate the radio wave to obtain the audio signal 244.

The main controller 400 can send the audio signal 241 to the motorcontroller 200. The motor controller 200 can thus receive the audiosignal 241 from the controller 200 via the control signal line 430and/or the data communication line 440 coupling the main controller 400with the motor controller 200.

FIG. 26 is an exemplary diagram illustrating another alternativeembodiment of the system 100 of FIG. 1, wherein the motor controller 200of the system 100 can include a signal converter 270. The signalconverter 270 can include an analog-to-digital converter (ADC)configured to convert an analog audio signal 244 to the audio signal 241that is digital.

The main controller 400 can be configured to receive the analog audiosignal 244 using any suitable method. For example, the communicationmodule 260 (shown in FIG. 6) on the motor controller 200 can receive aradio wave modulated with the audio signal 244. The processor(s) 210and/or other circuits on the controller 200 can be configured todemodulate the radio wave to obtain the audio signal 244.

Additionally and/or alternatively, the main controller 400 can transmitthe analog audio signal 244 to the motor controller 200. The motorcontroller 200 can thus receive the analog audio signal 244 from thecontroller 200 via the control signal line 430 and/or the datacommunication line 440 coupling the main controller 400 with the motorcontroller 200.

Using the systems 100 illustrated in FIGS. 25-26, a sound generated at aremote distance from the mobile platform 900 can be reproduced by themobile platform 900 in real time. For example, an input audio signal,such as an audible sound, an ultrasound wave, and/or an infrasound wave,can be converted to the analog audio signal 244 via a device such as amicrophone. The microphone can be coupled to a transmitter. Thetransmitter can be integrated with a computer device and/or a radiostation located remotely relative to the mobile platform 900. Thecomputer device and/or a radio station can modulate a radio wave withthe analog audio signal 244. The transmitter can transmit the modulatedradio wave to the system 100.

The system 100 can include a demodulator (not shown) on the motorcontroller 200 and/or the main controller 400 to demodulate the radiowave and obtain the analog audio signal 244. The analog audio signal 244can be processed by the system 100 as shown in FIGS. 25-26. The motor300 of the system 100 can be configured to generate the sound in realtime. The sound can replicate the input audio signal. For example, whenthe system includes a UAV, the UAV can generate a sound that can havethe same audio content as the remotely-generated input audio signal.

Additionally and/or alternatively, using the systems 100 illustrated inFIGS. 22-26, the sound 320 can be reproduced by the mobile platform 900in a time-delayed manner. For example, the analog audio signal 244 canbe generated at a remote distance from the mobile platform 900 andconverted to the audio signal 241 via an analog-to-digital converter(ADC) on a computer (not shown) remote from the mobile platform 900. Theaudio signal 241 can be stored in the audio file 243. The audio file 243can be transmitted by the computer to the communication module 460and/or the communication module 260 to be decoded into the audio signal241 subsequently (shown in FIGS. 23-24).

In another example, the analog audio signal 244 is converted to theaudio signal 241 via the signal converter 270 and/or the signalconverter 470 (shown in FIGS. 25-26). The motor controller 200 and/orthe main controller 400 can include an encoder for encoding the audiosignal 241 into the audio file 243. The audio file 243 can thereby bedecoded into the audio signal 241 subsequently (shown in FIGS. 22-24).

According to FIGS. 14, 16-21, the motor-driving signal 240 can bedirectly provided to the motor 300 for generating the sound 320 (shownin FIG. 6). Furthermore, the motor-driving signal 240 can be used forgenerating the sound 320 via additionally and/or alternatively ways.FIG. 27 is an exemplary diagram illustrating alternative embodiments ofthe system of FIG. 1, wherein the motor-driving signal 240 isdemodulated. As shown in FIG. 27, the motor-driving signal 240 outputtedby the motor controller 200 can be inputted into a demodulator 500. Themotor-driving signal 240 inputted into the demodulator 500 can includeone or more of the motor-driving signals 240A, 240B, 240C. Thedemodulator 500 can be at least partially integrated with and/orseparated from the system 100. The demodulator 500 shown in FIG. 27 canbe configured to extract the audio signal 241 from a carrier wave. Forexample, when the encoder 216 (shown in FIG. 15) modulates a pulsingsignal with the audio signal 241 by using PWM, the demodulator 500 canbe configured to remove the audio signal 241 from the pulsing signal.For example, the demodulate 500 can filter out the pulsing signal havinga sampling frequency of the PWM.

The demodulator 500 can include any processor and/or discrete circuitsfor separating the audio signal 241 from the pulsing signal. Anexemplary demodulator 500 can include one or more filters enabled tofilter a signal via a bandwidth from 20 Hz to 20 kHz, a band-pass filterhaving a bandwidth from 20 Hz to 20 kHz, and/or a low-pass filter havinga cut-off frequency of 20 kHz. Upon being processed by the demodulator500, the motor-driving signal 240 can be converted to a demodulatedaudio signal 245. The demodulated audio signal 245 can have a waveformsimilar and/or identical to the audio signal 241 shown in FIGS. 14,16-21. The demodulated audio signal 245 can drive a conventionalloudspeaker and/or headphone, to generate an audio content 321. Thesound 321 can be similar and/or identical to the sound 321.

In one example, upon being filtered by the band-pass filter having abandwidth from 20 Hz to 20 kHz, the motor-driving signal 240 can beenabled to drive the speaker 600 to generate the audio content 321consistent with the sound 320 generated by the motor 300. For example,the sound 320 can include oral speech. The motor-driving signal 240 isenabled to drive the loudspeaker 600 to generate the audio content 321including an oral content. The speech can be consistent with the oralcontent. For illustrative purposes, the speech can include a sentence‘remote control signal is lost.’ The oral content can include thesentence ‘remote control signal is lost’ audible to a human ear. Thatis, based on human hearing, the oral content can convey the samesyllables as the speech of the sound 320.

The oral content is not limited to human speech. For example, the sound320 can include animal sound. The motor-driving signal 240 is enabled todrive the loudspeaker 600 to generate the audio content 321 including anoral content consistent with the animal sound. For illustrativepurposes, the sound 320 can include a dog bark. The oral content caninclude the dog bark audible to a human ear. That is, based on humanhearing, the oral content can convey the same and/or similar syllables(or phonetics) as the sound 320.

In another example, the sound 320 can include music. The motor-drivingsignal 240 is enabled to drive the loudspeaker 600 to generate the audiocontent 321 including a musical content. The music can be consistentwith the musical content. For illustrative purposes, the music caninclude a tune of ‘Jingle Bells’. The oral content can include the tuneof ‘Jingle Bells’ audible to a human ear. That is, based on humanhearing, the musical content can convey the same melody and/or rhythm asthe music of the sound 320.

FIG. 27 illustrates both the sound 320 and the audio content 321 asgenerated, for illustrative purposes only. The sound 320 and the audiocontent 321 can be generated independent of each other. For example, themotor-driving signal 240 can drive the motor 300 to generate a soundduring an operation (e.g., landing, taking off, flight operation) of themobile platform 900. The mobile platform 900 does not necessarilyinclude the loudspeaker 600 and/or the demodulator 500. For analyzingand/or diagnosing the motor-driving signal 240, the loudspeaker 600and/or the demodulator 500 can be connected to the motor-driving signalline 230 of the motor controller 200 to intercept the motor-drivingsignal 240 (shown in FIG. 27).

FIG. 28 is an exemplary diagram illustrating alternative embodiments ofthe system 100 of FIG. 1, wherein the motor-driving signal 240 isfiltered. The motor-driving signal 240 is shown in FIG. 28 as beinginputted into a filter 510. The motor-driving signal 240 inputted intothe filter 510 can include one or more of the motor-driving signals240A, 240B, 240C.

The filter 510 can include a low-pass filter. An exemplary filter 510can have a cutoff frequency less than 20 Hz. Thus, the DC signals 2130A,2130B, 2130C can remain, and the audio signal 241 can be removed. Thefilter 510 can thus produce an output signal 245. When the motor-drivingsignal 240 inputted into the demodulator 500 includes the motor-drivingsignal 240A, the motor-driving signal 240B, or the motor-driving signal240C (shown in FIGS. 16-21), the output signal 245 can correspondinglyinclude the DC signal 2130A, the DC signal 2130B, or the DC signal2130A, respectively.

In other words, upon being filtered by a low-pass filter having a cutofffrequency of 20 Hz or lower, the motor-driving signal 240 can include aDC bias signal. The DC bias signal can include the DC signal applied bythe DC signal unit 213 (shown in FIG. 14).

As previously described above with reference to FIG. 6, the system 100can be installed on a mobile platform and/or a UAV. Further, variousembodiments disclosed herein provide a kit for assembling the system100, the mobile platform 900, and/or the UAV. The kit can be a kit forassembling the mobile platform and/or the UAV. The kit can include oneor more of the motor controller 200, the motor 300, and/or the maincontroller 400 as shown throughout the present disclosure, for example,in FIGS. 1, 6-26. The kit can be used for assembling the system 100instead of acquiring a factory-assembled system 100. In certainembodiments, an instruction manual can be included in the kit. Theinstruction manual may have instructions thereon. When an operatorand/or machine follows the instructions, the motor controller 200, themotor 300, and/or the main controller 400 can be assembled into thesystem 100 as shown in the present disclosure.

Further, the motor controller 200, the motor 300, and/or the maincontroller 400 is not necessarily pre-assembled, and may be assembledaccording to the instruction manual. For example, the stationary device340 and/or the movable device 330 (shown in FIG. 7) may be included inthe kit and configured to be coupled to each other according to theinstruction manual.

Various embodiments further disclose computer program product comprisinginstructions for generating sound in accordance with the methodsdisclosed herein, e.g., as shown in FIG. 2. The program/software can bestored in a (non-transitory) computer-readable storage medium including,e.g., Read-Only Memory (ROM), Random Access Memory (RAM), internalmemory, register, computer hard disk, removable disk, CD-ROM, opticaldisk, floppy disk, magnetic disk, or the like. The program/software caninclude coded instructions to instruct one or more processors on acomputer device to execute the methods in accordance with variousdisclosed embodiments.

FIG. 29 is an exemplary diagram illustrating an embodiment of anapparatus 201 for controlling the motor of FIG. 1. The apparatus 201 canfunction as an electronic speed control (ESC). In other words, theapparatus 201 can include the motor main controller 400 with referenceto FIGS. 1, 6, 14, and 16-26. The apparatus 201 can includemicroprocessor(s) and/or discrete circuit hardware for implementingfunctions of the apparatus 201 as disclosed herein.

As shown in FIG. 29, the apparatus 201 can include the encoder 216configured to encode the motor-driving signal 240 with the audio signal241 as shown in FIG. 14. The audio signal 241 can be digital. Theencoder 216 can be configured to modulate a pulsing signal with theaudio signal 241 to produce the motor-driving signal 240. The encoder216 can be configured to modulate the pulsing signal with the audiosignal 241 using PWM.

The encoder 216 can be configured to drive the motor 300 with themotor-driving signal 240 to generate the sound 320 corresponding to theaudio signal 241. The encoder 216 can be configured to vibrate the rotor330 of the motor 300 relative to the equilibrium position 380 of therotor 330 based upon the motor-driving signal 240.

The apparatus 201 can further include the DC signal unit 213 configuredto superimpose a direct current (DC) signal on the audio signal, the DCsignal being configured to adjust the equilibrium position 380 of therotor 330 relative to the stator 340. The DC signal unit 213 can beconfigured to change a volume of the sound 320 by adjusting theequilibrium position 380 of the rotor 330 relative to a stator 340 basedupon the motor-driving signal 240.

The apparatus 201 can further include a filter 204 configured to filterthe audio signal 241. The apparatus 201 can further include an amplifier212 configured to amplify the audio signal 241.

When the audio signal 241 is digital, the apparatus 201 can include thesignal converter 270 configured to convert an analog audio signal intothe audio signal 241.

The apparatus 201 can further include the communication module 260configured to receive the audio signal 241 from the main controller 400via a control signal line 430 and/or a data communication line 440(shown in FIG. 6) coupling the main controller 400 with the apparatus201. The apparatus 201 and/or the main controller 400 can be associatedwith the mobile platform 900. The signal converter 270 can receive theanalog audio signal from the main controller 400 (shown in FIG. 6)and/or another computer system (not shown) via the communication module260.

The apparatus 201 can further include the audio signal decoder 250configured to create the audio signal 241 by decoding the audio file 243(shown in FIGS. 23-24).

The communication module 260 can be configured to receive the audio file243 from the main controller 400 via the control signal line 430 and/orthe data communication line 440 coupling the main controller 400 withthe apparatus 201.

The apparatus 201 can further include the memory 220 for storing theaudio file 243. The apparatus 201 can be configured to retrieve theaudio file 243 from the memory 220. For example, the encoder 216, thefilter 214, the DC signal unit 213, the amplifier 212, the communicationmodule 260, and/or the audio signal decoder 250 can be configured toretrieve the audio file 243 from the memory 220.

The audio signal 241 can be processed by the amplifier 212, the DCsignal unit 213, the filter 214, and/or the encoder 216 sequentially asshown in FIG. 29, and similarly in FIGS. 14, 16-21. However, sequence ofthe amplifier 212, the DC signal unit 213, the filter 214, and/or theencoder 216 can be different from the sequence shown in FIGS. 14, 16-21,29. For example, the filter 214 can precede the DC signal unit 213.Further, the amplifier 212, the DC signal unit 213, the filter 214,and/or the encoder 216 can be omitted. For example, the amplifier 212and/or the filter 214 can be omitted.

In certain embodiments, functions of the encoder 216 can be implementedby one or more processors comprising integrated circuits. Functions ofthe filter 214, the DC signal unit 213, the amplifier 212 and/or thesignal converter 270 can be implemented by processor(s) and/or discretecircuits.

For illustrative purposes, methods and systems disclosed herein areshown as enabling the vibration 370 of the motor 300 when the system 100is stationary, i.e., the motor 300 is not causing the system 100 tomove. However, the methods and systems disclosed herein can enable thevibration 370 of the motor 300 while the motor 300 is generating amotion, such as a rotating motion, for moving the system 100. That is,the rotor 330 (shown in FIGS. 8-12) can rotate at the same time when thevibration 370 is implemented. For certain mobile platform applications,the rotor 330 does not need to rotate at a frequency equal to thefrequency of the audio signal. For the rotor 330 may rotate at afrequency (and/or number of cycles per unit time) lower than thefrequency of the audio signal. In that case, inertia of the rotor 330can enable the rotor 330 to rotate while the vibration 370 issuperimposed on the rotating motion.

According to the various disclosed embodiments, the motor 300 can beenabled to generate a high-quality sound while generating a mechanicalmotion. For example, the motor 300 can generate a high-quality soundwhile enabling the mobile platform 900 (shown in FIG. 6), such as a UAV,to move. The motor-driving signal 240 driving the motor 300 to generatethe sound 320 can be produced by computer-executable instructionswithout the need of installing addition hardware audio instrument. As aresult, without increasing weight and/or affecting a flight time, a UAVcan generate high-quality sound.

With the capability of generating high-quality sound, the mobileplatform (shown in FIG. 6), such as the UAV, can communicate with ahuman being in a user-friendly way. For example, when a UAV needs toinform a human that ‘remote control signal is lost’, conventionalcommunication conveys the message by using a certain light signal or asingle frequency beep. The human needs to look up in a manual for themessage, which can be time-consuming and prone to error. Using thedisclosed methods and systems, the UAV is able to generate the soundincluding the oral content ‘remote control signal is lost’. The humancan immediately understand the message without looking up the manual.Communication can thus be fast and accurate. User experience can begreatly improved.

Further, the mobile platform 900 (such as a UAV) may have multiplemotors 300, each driven by a respective motor controller 200. Each motorcontroller 200A can produce a respective motor-driving signal 240. Eachof the motors 300 can thus generate different/uniform sounds 320. Forexample, each motor 300 can generate a low-frequency component, amid-frequency component, and a high frequency component of a musicalpiece, such as different parts of a symphonic piece, to create astereo-like effect. Thus, the sound 320 can be of high quality andprovide entertaining experience to the human.

The disclosed embodiments are susceptible to various modifications andalternative forms, and specific examples thereof have been shown by wayof example in the drawings and are herein described in detail. It shouldbe understood, however, that the disclosed embodiments are not to belimited to the particular forms or methods disclosed, but to thecontrary, the disclosed embodiments are to cover all modifications,equivalents, and alternatives.

What is claimed is:
 1. A method for generating sound with a motor,comprising: generating a motor-driving signal having an audio signalcomponent; applying the motor-driving signal to the motor, wherein themotor-driving signal drives the motor to generate a sound correspondingto the audio signal component; applying a bandpass filter to themotor-driving signal to generate a filtered motor-driving signal; andapplying the filtered motor-driving signal to a speaker to present audiocontent consistent with the sound generated by the motor.
 2. The methodof claim 1, wherein the motor-driving signal is filtered by the bandpassfilter to a bandwidth of 20 Hz to 20 kHz.
 3. The method of claim 1,wherein generating the motor-driving signal includes generating theaudio signal component based on an audio signal.
 4. The method of claim3, wherein generating the motor-driving signal includes modulating apulse signal with the audio signal.
 5. The method of claim 4, whereinthe pulse signal is modulated with the audio signal using pulse-widthmodulation.
 6. The method of claim 4, further comprising receiving theaudio signal from a main controller of the mobile platform.
 7. Themethod of claim 4, further comprising decoding an audio file andobtaining the audio signal from the decoded audio file.
 8. The method ofclaim 1, wherein the motor-driving signal further has a direct-circuit(DC) component.
 9. The method of claim 8, further comprising: adjustinga volume of the sound generated by the motor by adjusting an equilibriumposition of a rotor relative to a stator of the motor.
 10. The method ofclaim 9, wherein adjusting the volume of the sound includes adjustingthe equilibrium position of the rotor by adjusting the DC component ofthe motor-driving signal.
 11. The method of claim 1, further comprisingamplifying the sound by vibrating a motor casing that at least partiallyencloses the rotor.
 12. The method of claim 1, wherein the motor-drivingsignal drives a rotor to vibrate relative to an equilibrium position togenerate the sound.
 13. The method of claim 12, wherein themotor-driving signal drives the rotor to vibrate along a radialdirection of the motor to generate the sound.
 14. The method of claim 1,wherein the motor-driving signal further drives the motor to enable amobile platform to move.
 15. A system for generating sound, comprising:a motor having a rotor; a speaker; and one or more processors configuredto: generate a motor-driving signal having an audio signal component;apply the motor-driving signal to the motor, wherein the motor-drivingsignal drives the motor to generate a sound corresponding to the audiosignal component; apply a bandpass filter to the motor-driving signal togenerate a filtered motor-driving signal; and apply the filteredmotor-driving signal to the speaker to present audio content consistentwith the sound generated by the motor.
 16. The system of claim 15,wherein the motor-driving signal is filtered by the bandpass filter to abandwidth of 20 Hz to 20 kHz.
 17. The system of claim 15, wherein themotor is configured to enable a mobile platform to move.
 18. The systemof claim 15, wherein the motor-driving signal further has adirect-circuit (DC) component, and the one or more processors arefurther configured to adjust a volume of the sound generated by themotor by adjusting the DC component of the motor-driving signal.
 19. Amobile platform, comprising: a motor controller configured to generate amotor-driving signal having an audio signal component; a speaker; and amotor being coupled to the motor controller, the motor having a rotor;wherein the motor controller is configured to: apply the motor-drivingsignal to the motor to generate a sound corresponding to the audiosignal component; apply a bandpass filter to the motor-driving signal togenerate a filtered motor-driving signal; and apply the filteredmotor-driving signal to the speaker to present audio content consistentwith the sound generated by the motor.
 20. The mobile platform of claim19, wherein the motor is driven by the motor-driving signal to generatethe sound comprising oral content to convey warning or error messageassociated with an operation of the mobile platform.